Department of Anaesthesia and Intensive Care, Sahlgrenska University Hospital, 413 45 Gothenburg, Sweden.
Acta Anaesthesiol Scand. 2010 Mar;54(3):370-6. doi: 10.1111/j.1399-6576.2009.02107.x. Epub 2009 Oct 15.
The functional residual capacity (FRC) is an important parameter in pediatric respiratory monitoring but it is difficult to assess in the clinical setting. We have introduced a modified N(2) washout method utilizing a change of F(I)O(2) of 0.1 for FRC measurement in adult respiratory monitoring. This study validated the algorithm in a pediatric lung model and investigated the stability and feasibility in a pediatric peri-operative and intensive care setting.
The lung model was ventilated in combinations of ventilatory modes, CO(2) production, model FRC and respiratory rates. Sixteen children from 10 days to 5 years were studied peri-operatively with controlled ventilation using a Mapleson D system and in the intensive care unit using a Servo-i ventilator in a supported spontaneous mode. FRC was measured during stable metabolic, respiratory and circulatory periods at positive end expiratory pressure of 3-4 and 7-8 cmH(2)O.
In the model and in the clinical setting, we found an excellent agreement between washout and washin measurements of FRC as well as acceptable coefficients of repeatability.
FRC was satisfactorily measured by a modified N(2) algorithm and may be included as a monitoring variable in pediatric respiratory care. Pediatric FRC monitoring demands strictly stable conditions as measurements are performed close to the limits of the monitor's specifications.
功能残气量（FRC）是小儿呼吸监测的一个重要参数，但在临床环境中难以评估。我们已经引入了一种改良的 N（2）冲洗法，利用 F（I）O（2）的 0.1 变化来测量成人呼吸监测中的 FRC。本研究在小儿肺模型中验证了该算法，并在小儿围手术期和重症监护环境中研究了其稳定性和可行性。
肺模型采用通气模式、CO（2）产生、模型 FRC 和呼吸频率的组合进行通气。16 名 10 天至 5 岁的儿童在围手术期使用 Mapleson D 系统进行控制性通气，并在重症监护病房使用 Servo-i 呼吸机进行支持性自主通气模式。在正呼气末压为 3-4 和 7-8 cmH（2）O 时，在代谢、呼吸和循环稳定期测量 FRC。
在模型和临床环境中，我们发现 FRC 的冲洗和冲洗测量之间具有极好的一致性，并且可重复性系数也可以接受。
改良的 N（2）算法可以满意地测量 FRC，可以作为小儿呼吸护理中的监测变量。儿科 FRC 监测需要严格稳定的条件，因为测量是在接近监测器规格极限的情况下进行的。
